Occupational asthma is a respiratory allergy that occurs with an obstruction of the respiratory tract, developing against the background of exposure to industrial allergens. Professional bronchial asthma is manifested by attacks of suffocation, coughing, expiratory shortness of breath, wheezing, which occur directly upon contact with trigger substances at work. To confirm the diagnosis, it is necessary to establish an association between professional activity and the occurrence of asthma symptoms. Allergy tests, provocative tests, and peak flowmetry are carried out. Treatment – exclusion of contact with the allergen (if possible), pharmacotherapy (desensitizers, bronchodilators, GCS, etc.), physiotherapy.
ICD 10
J45 Asthma
Meaning
Occupational asthma (OA) is bronchial asthma caused by interaction with various sensitizing substances in the workplace. When making a diagnosis of “occupational asthma”, it is important to take into account the absence of a previous history, i.e. the absence of a subclinical or clinical course of the disease at the time of starting work in these conditions. In industrialized countries, bronchial asthma of professional origin occurs in 2-15% of all cases of this pathology. In the structure of other occupational diseases, bronchial asthma accounts for about 12%. The high proportion of morbidity is explained by the intensive chemicalization of production and the constant appearance of new industrial allergens. Specialists in the field of occupational pathology, clinical pulmonology and allergology-immunology are engaged in the development of a medical strategy for occupational asthma.
Causes of occupational asthma
The etiology of occupational asthma is caused by the constant exposure to the respiratory tract of production agents. Their inhalation may be associated with a violation of technological processes, poor air conditioning in industrial premises, neglect of individual protective equipment. Production factors related to the development of OA are divided into inductors and triggers. The first of them (inducers) provoke an inflammatory reaction and hyperreactivity of the bronchi; the second (triggers) directly cause bronchial obstruction and exacerbation of occupational asthma. Non-infectious and infectious allergens act as inducers, meteorological factors, stress, hyperventilation, physical activity, active or passive smoking, or the same inducers (allergens, acute respiratory viral infections, exacerbation of rhinitis, sinusitis, etc.) can play the role of triggers.
Currently, more than 300 production factors provoking OA have been identified. Farmers, veterinarians, employees of laboratories and pet stores can have professional bronchial asthma caused by animal hair and hair, poultry feathers, bee products, feed, etc. Agricultural workers, bakers, textile and food industry workers are more likely to face respiratory allergies to plant proteins contained in grain and flour dust, cotton, linen, silk fiber, seeds. Workers employed in carpentry, furniture and woodworking industries suffer from inhalation of wood dust containing highly allergenic low molecular weight compounds. A common cause of occupational asthma in painters, dyers, construction workers is professional contact with paints, adhesives, solvents. Seafood (shrimps, crabs, shellfish) have a high sensitizing ability, so workers engaged in their extraction and processing are susceptible to the occurrence of OA.
The risk group for the development of occupational asthma includes workers in the pharmaceutical and chemical industries, medical workers (due to contact with medicines, detergents, latex gloves, disinfectants), hairdressers and nail service masters interacting with hair dyes, decorative lacquers and nail powder. In addition to OA, these and other individuals may develop allergic rhinitis, rhinopharyngitis, conjunctivitis, allergic dermatoses, eczema. Inhalation of certain substances (chlorine, iodine, fluorine, coal, silicates) can cause primary damage to the respiratory apparatus in the form of exogenous allergic alveolitis, dust bronchitis or pneumosclerosis, and occupational asthma is a complication of pneumoconiosis.
Symptoms of occupational asthma
Manifestations of occupational asthma in general do not differ from asthma of a different genesis. Before an attack of bronchial obstruction, there may be precursors: paroxysmal cough, sore throat, sneezing, rhinorrhea, difficulty breathing. Sometimes skin-allergic symptoms appear: itching, contact dermatitis, urticaria, Quincke’s edema.
An asthmatic attack occurs directly during work with sensitizers or shortly after its completion. There is a feeling of suffocation, expiratory shortness of breath, forcing the patient to take a sitting position with support on his hands, with the inclusion of breathing and tension of auxiliary muscles in the process. Noisy whistling breathing is heard, tachycardia occurs; the pallor of the skin draws attention. At the end of the attack, viscous transparent sputum is separated. In the early period of occupational asthma, a suffocation attack ends with the cessation of exposure to the industrial allergen; in the late period, the use of special inhalers is required to stop it. A prolonged or severe asthmatic attack may result in the death of the patient from asphyxia as a result of blockage of the bronchioles with viscous sputum.
With a mild form of occupational asthma, there are no clinical symptoms in the intercrime period. During the light interval, moderate shortness of breath associated with exercise, a slight cough with mucosal sputum may be felt in the moderate course of asthma. In severe cases, patients are diagnosed with chronic obstructive bronchitis, pulmonary heart, pulmonary emphysema and pneumosclerosis.
The clinical criteria on the basis of which occupational bronchial asthma is diagnosed are: the association of the occurrence of the disease with professional activity; the presence of other signs of occupational allergies (skin, respiratory, eye); a decrease in the severity or cessation of asthma symptoms on weekends and during vacation and deterioration of the condition when returning to work; reversibility of bronchial obstruction.
Diagnostics
In addition to clinical symptoms, the professional nature of bronchial asthma is confirmed by an analysis of the working conditions, the patient’s professional route, the data of the examination of the immune and allergological status. To do this, specialists are involved in the diagnosis: pulmonologists, allergologists, immunologists, otolaryngologists, dermatologists, but the diagnosis of OA is made only by a professional pathologist. The simplest diagnostic tests include peak flowmetry at home and in the workplace, elimination tests.
During the period of remission of occupational asthma, skin allergy tests with epidermal, dust, household, pollen allergens and provocative inhalation tests with industrial allergens are performed, presumably provoking the disease. Immunodiagnostics includes determination of general and specific IgE, circulating immune complexes, basophil degranulation reaction, serological reactions.
Chest x-ray can show changes characteristic of the late stages of the course of occupational asthma, therefore its main role is to exclude other pathology of the respiratory system. To assess the severity of asthma, the function of external respiration is investigated. Diagnoses-exceptions are atopic bronchial asthma, chronic bronchitis.
Treatment for occupational asthma
In the treatment of occupational asthma, the same principles are used as in other forms of the disease. An indispensable condition is the elimination of contact with the culpable allergens. Inhaled medications are selected for the patient to relieve asthmatic attacks (salbutamol, ipratropium bromide + phenoterol, etc.), as well as for long-term control of asthma symptoms (antihistamines, bronchodilators, inhaled and systemic glucocorticoids, mucolytics). Allergen-specific immunotherapy, as a method of pathogenetic therapy of occupational asthma, has not found wide application.
In the inter-approach periods, patients with occupational asthma are recommended balneotherapy, physiotherapy (UFO, laser therapy, speleotherapy), acupuncture, phytotherapy, physical therapy, percussion and vibration massage. The patient is taught methods of auto-training, meditation, breathing exercises. For some patients, timely vacation planning is recommended to prevent exacerbations.
Prognosis and prevention
The issue of further professional suitability of the patient is decided by a medical and labor examination. Depending on the age of the patient, the severity of asthma and the profession, it may be recommended to transfer an employee to a job that excludes contact with allergens; professional retraining; resolving the issue of disability and other options. In order to prevent the development of bronchial asthma of professional genesis, it is necessary to ensure proper sanitary and hygienic conditions and occupational safety requirements at work, careful professional selection of employees of harmful industries, regular professional examinations.
Literature
- Occupational asthma. Mapp CE, Miotto D, Boschetto P. Med Lav. 2006 Mar-Apr;97(2):404-9. link
- Future advances in work-related asthma and the impact on occupational health. Malo JL. Occup Med (Lond). 2005 Dec;55(8):606-11 link
- Asthma on the job: work-related factors in new-onset asthma and in exacerbations of pre-existing asthma. Torén K, Brisman J, Olin AC, Blanc PD. Respir Med. 2000 Jun;94(6):529-35. link
- Diisocyanate-induced asthma: diagnosis, prognosis, and effects of medical surveillance measures. Tarlo SM, Liss GM. Appl Occup Environ Hyg. 2002 Dec;17(12):902-8. link
- Occupational asthma. Malo JL, Chan-Yeung M. J Allergy Clin Immunol. 2001 Sep;108(3):317-28. link